1. Field of the Invention
The present invention relates generally to an optical power supply switching apparatus by which any number of electric appliances can be turned on or off through the medium of optical signals whenever power switches disposed at a position remote from the electric appliance are manually turned on or off, and more specifically to an optical switching apparatus for reducing electromagnetic interference between the controlled electric appliances and other audio equipment or electronic appliances.
2. Description of the Prior Art
The background of the present invention will be explained hereinbelow with respect to its application to an apparatus used in an automotive vehicle by way of example.
An automotive vehicle is generally equipped with various electric appliances, each having various electric loads such as motors, solenoids, air-conditioning system elements, etc. These electric appliances are operated or activated when the driver operates a corresponding manual switch in order to supply battery power to these appliances.
In electric appliances such are described above, however, in the case when a large current intermittently passes through the appliance via a power supply line, especially in the case of an electric appliance which includes inductive loads such as solenoids or motors, resonance phenomena due to the inductive impedance and stray capacitance within the appliance induce a high-frequency oscillation, thus generating high-frequency intermittent arcing across the contacts of relays. As a result, high-frequency, high-amplitude noise signals flow through the power supply line, resulting in electromagnetic noise which can be amplified through a car radio.
A more detailed description of the prior-art power supply switching apparatus will be described with reference to the attached drawing under DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS.